Utility vehicles (“UVs”) and all terrain vehicles (“ATVs”) are well known for travel over a wide variety of terrains, including over unpaved trails or fields, rocks, etc. Such vehicles are widely used in agriculture and forestry operations, as well as in safety operations such as for rugged mountain crossings. Such vehicles are also widely used for recreational enjoyment in natural, outdoor settings away from pavement.
UVs and ATVs commonly use internal combustion engines, including single and dual cylinder engines, which output exhaust gasses. An exhaust system is used to treat and expel exhaust gasses from the vehicle. Such exhaust systems commonly include a catalytic converter to catalyze a redox reaction in the exhaust gasses and a muffler to reduce noise, connected together with piping and leading to an exhaust pipe so the exhaust gasses are output at the desired location relative to the vehicle. Both the catalytic converter and the muffler are typically generally cylindrical structures, significantly greater in diameter than the piping. Further, more modern vehicles may include anon-board diagnostic (“OBD”) system, arranged near the catalytic converter, for real-time monitoring of the catalytic converter.
Particularly when the engine is centrally mounted between the vehicle tires rather than in front of the passengers, the space available for the components of the exhaust system is limited. The space constraints on UVs and ATVs can be much tighter than on many onroad passenger vehicles due to the smaller overall size of the UVs and ATVs. Dual cylinder engines, laid out front-to-rear on the UV or ATV to reduce width, may have one cylinder output exhaust gasses at the front of the engine and the other cylinder output exhaust gasses at the rear of the engine. Use of a two cylinder engine can accordingly make the space constrains even tighter than for a single cylinder UV or ATV, because the piping of exhaust gasses from each cylinder and joining the two exhaust flows can consume considerable space. Better exhaust systems, particularly suited for offroad vehicles such as UVs and ATVs, acceptable for use with dual cylinder front-to-rear mid mounted engines, are needed.